This invention relates to a turbine blade locking device for axial retention of a turbine blade on the turbine disk.
In the state of the art it is known to provide the blade roots of turbine blades with a profile to take up the radially directed forces occurring during the operation of a gas turbine. In order to prevent the blade root from moving axially relative to the turbine disk, a means of retention is required. Such means of retention are shown in Specifications EP 0 610 668 B1, U.S. Pat. No. 5,135,354 or U.S. Pat. No. 5,518,369 by way of example.
In the designs known from the state of the art, plate-type elements (locking plates, cover plates and locking rings) are usually fitted which, together with abutments on the blade roots or the turbine disks, provide for axial retention. Disadvantages here are the high assembly effort and the risk that these fixations may work loose or be inaccurately fitted, resulting in at least a slight axial displacement of the blade root relative to the turbine disk.
More particularly, cover plates, locking rings or locking plates, or a combination thereof, are used in the state of the art, which must be deformed, for example, bent, during assembly. A further disadvantage is the higher mass of the total design and the considerable manufacturing and assembly costs. Another disadvantage lies in the fact that serviceability and reliability are not always ensured or that relatively expensive inspection activities are required to check for correctness of assembly.